If you set the events at session or process level then oradebug dump events
4 will not show those as level 4 shows instance's event "template", which
then sessions or processes pick up when initialized. Only session and
process level events are really checked when running as usual, system level
events are just used as a template for new sessions/processes.

Normally the events set with FOREVER option should persist forever or until
disabled, but if an event is set with LIFETIME <x> keyword instead of
forever then they'll persist only <x> times they've occurred for a given
session or process.

> 9205 RAC, RH AS 2.1>> I know a level 1 errorstack trace of this event will dump the statement > that> failed at the instance level.> I set this event a while ago (months); much to my chagrin, the event was > not> there (the instance has not been bounced).> So, I guess this event also expires.>> I can see the life of an event trace using ORADEBUG DUMP EVENTS 4, but it> does not seem to change over time.> Is there any way to set the amount of time or determine how much longer an> event trace will be active?>> Does anyone know what the levels are of the 1652 event?>> TIA>> --> http://www.freelists.org/webpage/oracle-l>>